On the electrostatic component of protein-protein binding free energy

PMC Biophysics

Table 2 Slopes of the fitting lines and the corresponding correlation coefficients

Type of complex	Probe radius R = 1.4A and different ε(in)	ε(in) = 2 and different probe radius R	Slope of the fitting line	Correlation coefficient
Hetero, non-minimized	8.0	0.0	1.63	0.67
Hetero, minimized	8.0	0.0	1.31	0.59
Homo, non-minimized	4.0	0.0	1.22	0.72
Homo, minimized	4.0	0.0	1.23	0.85
Hetero, non-minimized	4.0	0.5	0.69	0.52
Hetero, minimized	4.0	0.5	0.92	0.79
Homo, non-minimized	4.0	0.5	1.44	0.87
Homo, minimized	4.0	0.5	1.34	0.85

The results are presented for the best correlations among ΔΔG_el calculated with "standard" probe radius of 1.4A versus small probe radius of 0.0 and 0.5A. The best correlations are those resulting in the best correlation coefficient and slope close to 1.0. In obtaining the best fits, the internal dielectric constant e(in) was varied (ε(in) = 1,2,4,8,20) in the ΔΔG_el calculations with "standard" probe radius of 1.4A.